Philip fitzsimons



(No Model.)

P. PITZSIMONS. TELEPHONE TRANSMITTER.

No. 453,581. Patented June 2,1891.

I I ms-Arro/iwfm NITED STATES PATENT OFFICE.

PHILIP FITZSIMONS, OF BIRMINGHAM, ALABAMA, ASSIGNOR OF ONE-HALF TOFREDERICK HARDY, OF SAME PLACE.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 453,581, dated June 2,1891.

Application filed September 9, 1890. Serial No. 364,396. (No model.)

To all whom it may concern:

Be it known that I, PHILIP Frrzsnuons, a citizen of the United States,residing at Birmingham, in the county of Jefferson and State of Alabama,have invented certain new and useful Improvements in Telephone-Transmitters; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates to telephone-transmitters and aims to reduce thenumber of the parts, to diminish the battery force required and increasethe durability and add to the usefulness of this class of instruments.

The improvement consists of the novel features which will be hereinaftermore fully described and claimed, and which are shown in the annexeddrawings, in which- Figure 1 is a diagrammatical view of atelephone-transmitter embodying my invention, showing the direction ofcircuits. Fig.2 is a modified form of electrodes to be attached to thediaphragm. Fig. 3 is a perspective view of the receiver-supporting hook.Fig. at is a detail perspective view of the central post which supportsthe carbon electrodes, showing it provided with a slot by means of whichthe electrodes can be replaced.

The parts are suitably incased and comprise the diaphragm A, as shown inthe accompanying drawings, of wood, Spanish cedar being preferredbecause of its non-conducting combined with vibratory qualities. Thisdiaphragm is stretched over a rigid frame A, and is securely fastenedthereto in such a manner that it will at all times be held under tensionboth longitudinally and laterally. By having the diaphragm held undertension its resonance is increased and it is not affected by dampness.The preferable Way of n1ounting the diaphragm is first to wet it,thereby expanding it to its fullest capacity, and then stretch it overand secure it to the frame. The carbon posts R R and T are supported onor secured to the diaphragm and have the ends of the carbon electrodes SS, which are placed between them, inserted in the sides thereof. Insteadof three posts, as shown in Fig. 1a central and two end posts-and havingthe carbon electrodes one on each side of the central post, two posts RR may be provided having the carbon electrodes supported between them,as shown in Fig. 2. The posts R R are connected together and withbinding-posts P P by wires Q Q.

The hook or shunt-lever G, on the outer forked end of which the receiveris supported, is made of a non-conducting material, such as vulcanizedrubber, celluloid, papier-mach, wood, or like material. The pin D,passing transversely through the end of the lever and projecting aboveand below the same for some distance, is electrically connected with thefulcrum B by the metal strip 0. The conducting-wire a connects the metalor conductingfulorum B with the push-button or switch B Theinduction-coil fires the terminals 0 O of the primary wire connectedwith the binding-posts P P and the post N, respectively, the secondarywires F and F being connected with the posts G and E, respectively. Thespring-arm m, attached to the plate M, to which the wires L and C areconnected, is adapted to bear on the post N and projects within the pathof the inner end of the hook or lever C. The wire 0 extends to the pushbutton or switch B and the wire L connects with the binding-post 76. Thepost D directly above the post E is connected by wire j with thebinding-post J, to which one wire from the bell J is attached, the otherwire from the bell being connected with the binding post J, which isgrounded through wire j. The wire a, extending from the switch orpush-button B has connection with. the hinding-post a, to which theline-wire is attached. The battery M has its poles in electricalconnection with the binding-posts'K and 7c.

The operation of the invention is as follows: The battery-current passesfrom the binding-post 7t by the wire L to the plate M and spring m,thence through the bindingpost N and wires 0 O of the primary circuitofthe induction-coil to the binding-posts P P, thence by the wire Q, Q tothe carbon posts R R, supporting the outside ends of the electrodes S S,through these electrodes to the central carbon post T and the wire X tothe bindingposts V V, thence to the binding-post K, completing thebattery-circuit. The in- ICO . ingpost K, and wire duced current-circuitis through the secondary circuit of the induction-coil by the wire F tothe binding-post E, through the pin D, plate 0, fulcrum B, wire apush-button B and wire a? to the binding-post a, to which the line-wireis attached, back through ground to binding-post J and wire I tobinding-post H, by double wire cord E to receiver F and back tobinding-post G, completing the circuit through wire F. The push-button Bis a three-pointswitch, through which the linewire a passes from thebinding-post a to the fulcrum B, except when the button is pressed, whenthe current from the binding-post 7c is sent through the wires L, 0 and0, out over the line, ringing the bell at the other end, the currentbeing grounded through wire 71: bind- WVhen the receiveris placed on thehook, the spring m is detached from the binding-post N, breaking theprimary or battery circuit. The pin D then being in contact with thebinding-post D the current received over the line would pass from thebinding-post D through the bell to ground at J. The vibration of thediaphragm causes a variation of the current in theprimary circuit bycausing a variation of pressure between the electrodes and thesupporting-posts, in which the holes are suffi ciently large to allowfree play of the electrodes. This produces a corresponding variation inthe induced current of the secondary circuit, which variation istransmitted over the line. One cell is suflieient to operate thetelephone above described, whereas other carbon telephones having agreater number of electrodes require greater battery-power. Tofacilitate the removal and the replacement of the electrodes S S, thecentral support T is provided in its side with a slot through which thereduced ends of the electrodes are passed when removing or replacing thesaid electrodes.

In Fig. 2 the electrodes S S are arranged in parallel position andsupported at their ends in posts R R, which are in electrical connectionwith the binding-posts P P and V V by means of the wires Q Q.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is

In a telephone-transniitter, the combination of the posts D N, and E,forming terminals of the bell-circuit, primaryand secondary wires of theinduction-coil, respectively, the plate M, forming terminal of thebattery and having spring m, which is adapted to make electricalconnection with the post N and the hook O, of non-conducting material,having metal conductor 0, and the transversepin D, the end projectingwithin the path of the spring m, substantially as and for the pur posedescribed.

In testimony whereof I affix my, signature in presence of two witnesses.

PHILIP FITZSIMONS. Witnesses:

J OHN T. RICHARDSON, F. HARDY.

